Explanation:
Cartesian coordinate system
A Cartesian
coordinate system specifies
each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two
fixed perpendicular directed lines, measured in the same unit of length.
Each reference line is called a coordinate
axis or just axis of the system, and the point where
they meet is its origin.
The coordinates can also be defined as the positions of the perpendicular projections of the point onto the two axes,
expressed as signed distances from the origin.
Cartesian coordinates in
two dimensions
The modern Cartesian coordinate system in two dimensions (also
called a rectangular coordinate system) is defined by an ordered pair of perpendicular lines (axes), a single unit of length
for both axes, and an orientation for each axis. (Early systems allowed
"oblique" axes, that is, axes that did not meet at right angles.) The
lines are commonly referred to as the x
and y-axes where the x-axis is taken to be
horizontal and the y-axis
is taken to be vertical. The point where the axes meet is taken as the origin
for both, thus turning each axis into a number line. For a given point P, a line is drawn through P perpendicular to the x-axis to meet it at X and second line is drawn through P perpendicular to the y-axis to meet it at Y. The coordinates of P are then X and Y interpreted as numbers x and y on the corresponding number lines. The
coordinates are written as an ordered pair (x, y).
The point where the axes meet is the common origin of the two
number lines and is simply called the origin.
It is often labeled O and if so then the axes are called Ox and Oy.
A plane with x and y-axes
defined is often referred to as the Cartesian plane or xy plane. The value of x is called the x-coordinate or abscissa and the value of y is called the y-coordinate or ordinate. (Our solved example in
mathguru.com uses this concept)
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
The above explanation is copied from
Wikipedia, the free encyclopedia and is remixed as allowed under the Creative
Commons Attribution- ShareAlike 3.0 Unported License.